Rotary hook for sewing machines



arch 31, 1936. U 2,035,985-

ROTARY HOOK FOR SEWING MACHINES Filed Nov. 50, 1934 2 Sheets-Sheet 1 March 31, 1936. G A E' I ROTARY HOOK FOR SEWING MACHINES Filed Nov. 30, 1934 2 Sheets-Sheet 2 Patented Mar. 31, 1936 PATENT OFFICE ROTARY noon FOR SEWING moms George Sauer, Berwyn, Ill., assignor to Union Special Machine Company, Chicago, 111., a corporation of Illinois Application November 30, 1934, Serial No. 755,495

8 Claims. (Cl. 112-256) The present invention relates to new and useful improvements in a rotary hook for a lockstitch sewing machine and more particularly to improved means for furnishing lubricant to the interengaging parts between the rotary hook and the stationary bobbin casing.

Anobject' of 'the invention is to provide, in a sewing machine; means for furnishing lubricant to the interengaging parts between the rotary hook and the stationary bobbin casing wherein means are provided for delivering lubricant from the end of the bushing for the rotary hook actuating shaft to an inclined surface on the hub of the rotary hook and wherein the lubricant is thus caused to flow by centrifugal force to the interengaging parts.

A further object of. the invention is to provide, in a sewing machine, means for furnishing lubricant to the interengaging parts between the rotary hook and the stationary bobbin casing wherein the end of the bushing for the hook actuating shaft and the hub of the rotary hook are fitted in overlapping relationship in a manner to permit lubricant to be delivered by gravity wherein means are provided for causing the lubricant to flow from the hub of the hook-to the interengaging parts by centrifugal force.

The above and other objects of the invention will in part be obvious and will be hereinafter more fully pointed out.

In the accompanying drawings:

Figure 1 is a side elevation, in section, showing the assembled rotary hook, the actuating shaft therefor and the bushing within which the shaft rotates.

Figure 2 is a sectional view along line 2-2 of Fi 1. 3

Figure 3 is a side elevation, in section, similar to Fig. 1 but showing another form of the invention.

Figure 4 is a sectional view along line 4-4 of Fig. 3'.

Figure 5 is a sectional view along line 5-5 of Fig. 3.

The invention relates generally to the provision of lubricating means'for furnishing lubricant to the interengaging parts between the rotary hook and the stationary bobbin casing. The rotary hook is fixed to the end of a rotating shaft and the bobbin casing is mounted-within and supported by the rotary hook. The bobbin casing is provided with a circumferential rib which engages a groove or raceway in the rotary hook andthus prevents lateral movement from the bushing to the hub of the hook and of the bobbin casing relative to the rotary hook. 'A portion of the bobbin casing engages a fixed part of the sewing machine in order to prevent rotation of the casing within the rotary hook. The actuating shaft for the rotary'hook is supported in a bushing which is mounted in a bearing bracket depending from the work support of the sewing machine. The shaft bushing is provided with a groove through which lubricant may flow from a source of supply to the 10 end thereof. The hub of the rotary hook and the end of the bushing are constructed in such a manner that they fit together in overlapping relationship. The hub is provided with an inclined portion to which lubricant flows by gravity from the groove in the bushing. The inclined portion on the hub of the rotary hook. passes through the rear face of the hook so that lubricant may flow to the inclined inner face of the hook rim along which it is caused to flow 20 to the interengaging parts by centrifugal force. Referring more in detail to the accompanying drawings and particularly, at this time, to Figs. 1' and 2, the invention is shown as applied to a sewing machine having a work support II) which 25 is provided with a depending bearing bracket H in which is mounted abushing l2. The actuating shaft I3 is mounted within the bushing 12 and the rotary hook I4. is secured to the end of the shaft by a screw l5 or the like. The particu- 30 lar manner in which the actuating shaft for the rotary hook is driven forms no part of the present invention and it is to be clearly understood that it may be driven in any suitablemanner. For purposes of illustration, however, the shaft I3 may be driven .by suitable intermeshing gears, as shown in the copending application of George Sauer, Serial No. 688,512, filed September 7, 1933, and described in detail in the copending application of Norman V. Christensen et al., Serial No. 670,186, filed May 9, 1933. The shaft ,may also be driven in the manner shown and described in the copending applications of George Sauer, Serial Nos. 716,415 and 716,416, filed March 19. 1934.

The rotary hook it is of usual cup-shaped construction having a rim portion l6 and a hub I! joined to the rim by a rear face portion 18. The hub is conical in longitudinal section, the larger end being adjacent the rear face of the hook. One side wall of the cup is cut away to provide -a hook which is adapted to enter the needle thread loop and carry the same about the bobbin casing l9 which is also cup-shaped and is adapted to receive a bobbin 20 therein. The bobbin is formed around a 26 to the recess 21 in the bushing and held within the bobbin casing it by a cover or carrier 2i. The bobbin casing is is provided with a. circumferential rib 22 which fits within a groove or raceway 23 in the rim portion it of the rotary hook.' The rib 22 and raceway 23 form interengaging parts between the rotary hook and the bobbin casing to prevent lateral movement of the casing relative to the hook. The bobbin casing is provided with a projecting portion 28 which engages a fixed part of the sewing machine in order to prevent the rotation thereof within the hook. The rotary hook operates in the usual manner and further description thereof is not considered necessary.

The depending bearing bracket ii is provided with an oil hole 25 which communicates with an opening 26 in the bushing l2.- The opening 26 in the bushing communicates with a recess 2'! portion of the inner periphery of the bushing. An axial groove 28 in the bushing leads from the recess therein to a vertical groove 29 formed in the end thereof. The free end of the bushing is ofiset to provide a reduced portion 30 which fits within a recess 38 formed in the end of the hub H; The recess ii is bounded by a wall portion 32 which is inclined toward the reduced end 30 of the bushing in order to pre-- vent the escape of lubricant therefrom. The hub I 1 is provided with an inclined port 32 which extends from the recess 38 to the inner face of the rotary hook. Oil admitted to the oil hole 25 in the bracket i I will flow through the opening from there it will follow the axial groove 28 and descend by gravity through the groove 29 to the recess 30 in the hub. As the hook rotates, the oil will be caused to flow through the port 33 to the inner face of the hook by centrifugal force which will cause it to follow the inclined inner face 34 of the rim portion Hi to the interengaging parts between the hook and the bobbin casing, that is, to

the interfitting rib 22 and raceway 23 in order to lubricate the same. 1

In Figs. 3, 4, and 5 of the accompanying drawings, a slightly modified form of the invention is shown. The bobbin 20, bobbin casing l9 and the rotary hook are assembled in the same manner described in connection with Fig. 1 and further description thereof is not considered necessary at this time. Oil admitted to the oil hole 26 in the depending bearing bracket l I the opening 26 in the bushing 21 therein, through the through the In to the recess Oil will pass from the recess 21 groove 28a in the bushing and then vertical groove 29a at the end thereof. The free end of the bushing l2a is offsetto provide an enlarged recessed or flanged portion 30a which fits over the smaller end of the tapered hub Ila of the rotary hook. The rear face l8aof the rotary hook is provided with a groove 31 atthe inner edge of the hub "a. Inclined ports 36 extend through the face of the rotary hook from the groove 31' to the inner face thereof. Oil descending the groove 29a in the end of the bushing l2a. will be picked up by the inclined surface 35 of the hub and will be caused to flow into the groove 31 from which it will find its way through ports 36 to the inclined inner face 34 of the rim I6 and will be caused to reach the interengaging parts between the bobbin casing and the rotary hook by centrifugal force occasioned by the rotation of the hook.

From the foregoing description, it will be seen that highly efflcient means for furnishing lubricant to the inter-enga ing parts between the a means for directing rotary hook having a hub,

acsaees rotary hook and the stationary bobbin casing is herewith provided and it is to be clearly understood that minor changes in the details of construction and arrangement of parts may be made without departing from the scope of the invention as set forth in the appended claims.

Having thus described the invention, what I claim as new and desire .to secure by letters Patent is:

1. In a sewing machine, the combination of a rotary hook having a hub and a rim portion, a stationary bobbin casing supported within said hook, a shaft on which said hub is mounted, said casing and rim portion having interengaging parts to prevent relative lateral movement between said casing and said hook, said hub having an oil conducting path substantially co-extensive therewith and inclined lengthwise thereof, means disposed exteriorly of said shaft for delivering oil thereto, and means including said oil conducting path for furnishing lubricant to said interengaging parts by centrifugal force.

2. In a sewing machine, the combination of a rotary hook havinga hub, a stationary bobbin casing supported within saidhook, said casing and hook having interengaging Parts'to prevent relative lateral movement therebetween, an actuating shaft on which said hub is secured, a bushing within which said shaft rotates, means for supplying lubricant from the end of said bushing to said hub, and means including a lubricant path on said hub for furnishing lubricant to said interengaging parts, said lubricant path extending from a point adjacent the end of said bushing to the opposite end of said hub and inclined throughout the length thereof.

3. In a sewing machine, the combination of a rotary hook having a hub and a rim portion, said rim portion having an inclined inner face, a stationary bobbin casing supported within said hook, said casing and rim parts to prevent relative lateral movement between said casing and said hook, an actuating shaft on which said hub is secured, a bushing within which said shaft rotates, said bushing having an axial groove leading to the end thereof, means for furnishing lubricant to said groove, said hub and the end of said bushing having overlapping portions whereby lubricant may pass from the end of said bushing to said hub, and lubricant from said hub to the inner face of said rim portion whereby lubricant is caused to flow by centrifugal force to said interengaging P rts.

4. In a sewing machine, the combination of a rotary hook having a hub and rim portion connected by a face portion, a stationary bobbin casing supported within said hook, a shaft on which said hub is mounted, said casing and rim portion having interengaging parts to prevent relative lateral movement between said casing and said hook, said hub having a port disposed entirely within the hub and inclined lengthwise thereof and extending to the inner surface of said face portion, and means disposed exteriorly of said shaft for delivering lubricant to said port whereby lubricant is caused to flow to the inner face of said rim portion and to said interengaging parts by centrifugal force.

5. In a sewing machine. he combination of a a stationary bobbin casing supported within said hook, said casing and hook having intereng ing parts to prevent relative lateral movement therebetween, an actu ating shaft on which said hub is secured, a bush,-

40 portion having interengaging ing within which said shaft rotates, said bushing having an oil conduit leading to the end thereof, said hub having a flange portion overlapping the end of said bushing and forming an annular recess whereby oil may flow thereto from the end of said bushing, and means for' directing lubricant from said recess to said intereng'aging parts.

6. In a sewing machine, the combination of a rotary hook having a hub, a stationary bobbin casing supported within said hook, said casing and hook having interengaging parts to prevent relative lateral movement therebetween, an actuating shaft on which said hub is secured, a bushing within which said shaft rotates, said bushing having an oil conduit leading to the end thereof, the end of said bushing being provided with an annular flange overlapping the end of said hub wherebyto permit lubricant to flow to said hub,- and means for directing lubricant from said hub to said interengaging partsl 7. In a sewing machine, the combination of a rotary hook having a hub, a rim portion and a connecting face portion, said face portion having an annular groove on the rear surface thereof and inclined ports leading from. said groove to the inner surface .of said face portion, of a stationary bobbin casing supported within said hook,

, said casing and rim portion having interengaglng parts to prevent relative lateral movement between said casing and said hook, and means for furnishing lubricant to said groove whereby the lubricant will be caused to flow by centrifugal force through said ports to said interengaging parts.

8. In a sewing machine, the combination of a rotary hook having a hub, a rim portion and a connecting face portion, said face portion having an annular groove on the rear surface thereof and inclined ports leading therefrom to the inner surface thereof, of a stationary bobbin casing supported within said hook, said casing and rim portion having interengaging parts to prevent relative lateral movement between said casing and said hook, said hub having an inclined outer surface merging into said groove, an actuating shaft on which said hub is secured, a bushing in which said shaft rotates, said bushing having a flanged end overlapping the smaller end of said hub, means for furnishing lubricant from the end of said bushing to the inclined surface of said hub whereby lubricant will be caused to flow by centrifugal force to said interengaging parts.

GEORGE BAUER. 

